Remove the pumpkin stem and scrub the pumpkins well.
Using a large knife to cut the pumpkin is half. Then use a spoon to scoop out the seeds and place them in a bowl (if planning to roast later).
Then brush the cut side of the pumpkin with olive oil. Turn and place the pumpkin halves, cut-side down onto a metal rimmed baking sheet and roast for 40 minutes or until a knife glides through the skin and flesh effortlessly. Larger pumpkins may need a little more time.
Allow the halves to cool until safe to handle. Use a spoon to scoop out all of the pumpkin flesh and adding it into your food processor, securing the lid and pureeing until smooth. You may need to stop it once to scrape down the sides in order to get the pumpkin to be fully pureed.
Store in pre-measured, freezer-safe containers or bags until ready to use, you can store in freezer for up to 3 to 6 months.
NOTE: I use this method for roasting butternut squash as well.